Querying

Hopefully this post goes some way in helping the reader understand better what hashing, hash indexes are and the need for row chains with In-memory Tables (Hekaton) in SQL Server 2014 hash indexes. Purpose of hashing? Hashing can be used to index character data, instead of building an index on a varchar(50) column for example, […]

Part 2 (Basics of the method in SQL Server) explained how to get data into a Bloom Filter structure, it now needs persisting. This post explains a method on how a Bloom Filter can be stored in a SQL Server database – I assume you have read Part 1 and Part 2 and understand about […]

Part 1 addressed Bloom Filter Concepts, if you haven’t already done so its important to start there. In this post I will show the basics of how we set and query the bit array that holds our Bloom Filter structure. Step 1 – Hash the target Data element (key) Multiple hash functions are used over your […]

Given a 10 million row table with a GUID as a primary key, we have a 50,000 row table that we want to look up to see if we have any matching rows and for those matching rows aggregate the data – lets assuming that 50% of the rows have a corresponding match – so […]